### Method

# GLib Hmac update

since: 2.30

#### Declaration [src]

    void
    g_hmac_update (
      GHmac* hmac,
      const guchar* data,
      gssize length
    )

#### Description [src]

Feeds `data` into an existing `GHmac`.

The HMAC must still be open, that is `g_hmac_get_string()` or `g_hmac_get_digest()` must not have been called on `hmac`.

Available since: 2.30

#### Parameters

`data`

  Type: An array of `guchar`

  Buffer used to compute the checksum.

  The length of the array is specified in the `length` argument.
  The data is owned by the caller of the method.

`length`

  Type: `gssize`

  Size of the buffer, or -1 if it is a nul-terminated string.